Factual error: When Packard and his men arrive on the island, they are seen wearing ALICE gear (All-purpose Lightweight Individual Carrying Equipment). The film takes place in 1973, that type of gear would've just finished testing phases in 1973. The soldiers would be more accurately equipped with M-1956 Load-Carrying Equipment (LCE) or M-1967 Modernized Load-Carrying Equipment (MCLE).
Continuity mistake: During the arrival to the island there are 11 choppers. The first time Kong appears he takes down two. In the next sequence where they all see him for the first time 11 choppers still fly by Kong.
Continuity mistake: During the final fight between Kong and the big Skull Crawler, Kong has the girl in his right hand. The Skull Crawler wraps its tongue around Kong's right arm, the fight ensues. Kong rears back and pulls the Skull Crawler's tongue and insides out of its mouth, still holding the girl. Point of view cuts to foreground and we see the Skull Crawler fall, lifeless, to the ground while Kong standing in background with his right hand open. Seconds later, Kong opens his right hand to set the girl down.
Factual error: When she is detailing her military experience Mason mentions she was "embedded with MACV-SOG." The practice of embedding journalists with military units during wartime did not become a formal practice until the Iraq War of 2003. Prior to that many journalists during the Vietnam War, like Joe Galloway who was with the 7th Cavalry at the Ia Drang Valley, had to find their own way to the battlefield. Additionally "embedding" was not a term that would have been used by the military or the press at that time.
Factual error: Despite being an alleged former SAS member, James Conrad not only "sweeps" (passes the muzzle of his weapon across the bodies of someone he doesn't want to shoot) several people, he fires directly over the head of Mason Weaver while she is standing within five feet of him. Any trained professional would avoid both of these as they could easily result in the friendly fire injury or death of a team member.